Description ²

The striped barnacle, Balanus amphitrite, is a medium-sized surface-fouling, sessile barnacle with distinct vertical bands of purple stripes on it's protective rigid housing plates, known as capitulum plates. It is conical in appearance and largest at the base, with a diamond-shaped opening protected by a movable opercular lid composed of two symmetrical triangular halves. Each of these halves contains two plates, the tergum and the scutum. The operculum opens when is the lid halves are flexed out to the sides (Cohen 2005).B. amphitrite is an acorn barnacle (Suborder Balanomorpha). Like all members of the taxon, it resides within a protective wall of rigid plates and is attached by its base directly to solid substrata. In contrast, goose barnacles attach by means of slender, flexible stalks (Cohen 2005).

Distribution ³

Balanus amphitrite is a common, broadly distributed coastal and estuarine biofouling organism found on hard natural surfaces such as rocks, in oyster beds, red mangrove (Rhizophora mangle) prop roots and mollusc shells. It is also found on artificial substrates like ship hulls, pilings, riprap, and seawalls.The native range of B. amphitrite is uncertain, but may be located in the Indian Ocean to the southwestern Pacific, based on its presence in the Pleistocene fossil record (Cohen 2005). It is now a dominant fouling organism found in warm and temperate waters worldwide (Desai et al. 2006).

In Lake Merritt ⁴

Look for large, nickel/quarter sized barnacles with reddish lines running down the sides.

Sources and Credits

1. (c) Auguste Le Roux, some rights reserved (CC BY-SA), https://upload.wikimedia.org/wikipedia/commons/5/5d/Balanus_amphitrite_7631.JPG
2. Adapted by Ken-ichi Ueda from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11525663
3. Adapted by Ken-ichi Ueda from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11525664
4. (c) Ken-ichi Ueda, some rights reserved (CC BY-SA)

More Info

• iNat taxon page
• Animal Diversity Web
• Atlas of Living Australia
• Beach Barnacles of New Zealand
• Beach Barnacles Of New Zealand
• Biodiversity Heritage Library
• BOLD Systems BIN search
• BugGuide
• CalPhotos
• Global Biodiversity Information Facility (GBIF)
• NatureServe Explorer 2.0
• SeaLifeBase
• World Register of Marine Species
• 日本のレッドデータ検索システム

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